// SPDX-License-Identifier: GPL-2.0-only #include <linux/export.h> #include <linux/bvec.h> #include <linux/fault-inject-usercopy.h> #include <linux/uio.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/splice.h> #include <linux/compat.h> #include <linux/scatterlist.h> #include <linux/instrumented.h> #include <linux/iov_iter.h> static __always_inline size_t copy_to_user_iter(void __user *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } static __always_inline size_t copy_to_user_iter_nofault(void __user *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } static __always_inline size_t copy_from_user_iter(void __user *iter_from, size_t progress, size_t len, void *to, void *priv2) { … } static __always_inline size_t memcpy_to_iter(void *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } static __always_inline size_t memcpy_from_iter(void *iter_from, size_t progress, size_t len, void *to, void *priv2) { … } /* * fault_in_iov_iter_readable - fault in iov iterator for reading * @i: iterator * @size: maximum length * * Fault in one or more iovecs of the given iov_iter, to a maximum length of * @size. For each iovec, fault in each page that constitutes the iovec. * * Returns the number of bytes not faulted in (like copy_to_user() and * copy_from_user()). * * Always returns 0 for non-userspace iterators. */ size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size) { … } EXPORT_SYMBOL(…); /* * fault_in_iov_iter_writeable - fault in iov iterator for writing * @i: iterator * @size: maximum length * * Faults in the iterator using get_user_pages(), i.e., without triggering * hardware page faults. This is primarily useful when we already know that * some or all of the pages in @i aren't in memory. * * Returns the number of bytes not faulted in, like copy_to_user() and * copy_from_user(). * * Always returns 0 for non-user-space iterators. */ size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size) { … } EXPORT_SYMBOL(…); void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, unsigned long nr_segs, size_t count) { … } EXPORT_SYMBOL(…); size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); #ifdef CONFIG_ARCH_HAS_COPY_MC static __always_inline size_t copy_to_user_iter_mc(void __user *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } static __always_inline size_t memcpy_to_iter_mc(void *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } /** * _copy_mc_to_iter - copy to iter with source memory error exception handling * @addr: source kernel address * @bytes: total transfer length * @i: destination iterator * * The pmem driver deploys this for the dax operation * (dax_copy_to_iter()) for dax reads (bypass page-cache and the * block-layer). Upon #MC read(2) aborts and returns EIO or the bytes * successfully copied. * * The main differences between this and typical _copy_to_iter(). * * * Typical tail/residue handling after a fault retries the copy * byte-by-byte until the fault happens again. Re-triggering machine * checks is potentially fatal so the implementation uses source * alignment and poison alignment assumptions to avoid re-triggering * hardware exceptions. * * * ITER_KVEC and ITER_BVEC can return short copies. Compare to * copy_to_iter() where only ITER_IOVEC attempts might return a short copy. * * Return: number of bytes copied (may be %0) */ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL_GPL(…); #endif /* CONFIG_ARCH_HAS_COPY_MC */ static __always_inline size_t __copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) { … } size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); static __always_inline size_t copy_from_user_iter_nocache(void __user *iter_from, size_t progress, size_t len, void *to, void *priv2) { … } size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); #ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE static __always_inline size_t copy_from_user_iter_flushcache(void __user *iter_from, size_t progress, size_t len, void *to, void *priv2) { … } static __always_inline size_t memcpy_from_iter_flushcache(void *iter_from, size_t progress, size_t len, void *to, void *priv2) { … } /** * _copy_from_iter_flushcache - write destination through cpu cache * @addr: destination kernel address * @bytes: total transfer length * @i: source iterator * * The pmem driver arranges for filesystem-dax to use this facility via * dax_copy_from_iter() for ensuring that writes to persistent memory * are flushed through the CPU cache. It is differentiated from * _copy_from_iter_nocache() in that guarantees all data is flushed for * all iterator types. The _copy_from_iter_nocache() only attempts to * bypass the cache for the ITER_IOVEC case, and on some archs may use * instructions that strand dirty-data in the cache. * * Return: number of bytes copied (may be %0) */ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL_GPL(…); #endif static inline bool page_copy_sane(struct page *page, size_t offset, size_t n) { … } size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); size_t copy_page_to_iter_nofault(struct page *page, unsigned offset, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); static __always_inline size_t zero_to_user_iter(void __user *iter_to, size_t progress, size_t len, void *priv, void *priv2) { … } static __always_inline size_t zero_to_iter(void *iter_to, size_t progress, size_t len, void *priv, void *priv2) { … } size_t iov_iter_zero(size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); size_t copy_page_from_iter_atomic(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { … } EXPORT_SYMBOL(…); static void iov_iter_bvec_advance(struct iov_iter *i, size_t size) { … } static void iov_iter_iovec_advance(struct iov_iter *i, size_t size) { … } void iov_iter_advance(struct iov_iter *i, size_t size) { … } EXPORT_SYMBOL(…); void iov_iter_revert(struct iov_iter *i, size_t unroll) { … } EXPORT_SYMBOL(…); /* * Return the count of just the current iov_iter segment. */ size_t iov_iter_single_seg_count(const struct iov_iter *i) { … } EXPORT_SYMBOL(…); void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec, unsigned long nr_segs, size_t count) { … } EXPORT_SYMBOL(…); void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec, unsigned long nr_segs, size_t count) { … } EXPORT_SYMBOL(…); /** * iov_iter_xarray - Initialise an I/O iterator to use the pages in an xarray * @i: The iterator to initialise. * @direction: The direction of the transfer. * @xarray: The xarray to access. * @start: The start file position. * @count: The size of the I/O buffer in bytes. * * Set up an I/O iterator to either draw data out of the pages attached to an * inode or to inject data into those pages. The pages *must* be prevented * from evaporation, either by taking a ref on them or locking them by the * caller. */ void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray, loff_t start, size_t count) { … } EXPORT_SYMBOL(…); /** * iov_iter_discard - Initialise an I/O iterator that discards data * @i: The iterator to initialise. * @direction: The direction of the transfer. * @count: The size of the I/O buffer in bytes. * * Set up an I/O iterator that just discards everything that's written to it. * It's only available as a READ iterator. */ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) { … } EXPORT_SYMBOL(…); static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, unsigned len_mask) { … } static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, unsigned len_mask) { … } /** * iov_iter_is_aligned() - Check if the addresses and lengths of each segments * are aligned to the parameters. * * @i: &struct iov_iter to restore * @addr_mask: bit mask to check against the iov element's addresses * @len_mask: bit mask to check against the iov element's lengths * * Return: false if any addresses or lengths intersect with the provided masks */ bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, unsigned len_mask) { … } EXPORT_SYMBOL_GPL(…); static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) { … } static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) { … } unsigned long iov_iter_alignment(const struct iov_iter *i) { … } EXPORT_SYMBOL(…); unsigned long iov_iter_gap_alignment(const struct iov_iter *i) { … } EXPORT_SYMBOL(…); static int want_pages_array(struct page ***res, size_t size, size_t start, unsigned int maxpages) { … } static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa, pgoff_t index, unsigned int nr_pages) { … } static ssize_t iter_xarray_get_pages(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned maxpages, size_t *_start_offset) { … } /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size) { … } /* must be done on non-empty ITER_BVEC one */ static struct page *first_bvec_segment(const struct iov_iter *i, size_t *size, size_t *start) { … } static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, size_t *start) { … } ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages, size_t maxsize, unsigned maxpages, size_t *start) { … } EXPORT_SYMBOL(…); ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages, size_t maxsize, size_t *start) { … } EXPORT_SYMBOL(…); static int iov_npages(const struct iov_iter *i, int maxpages) { … } static int bvec_npages(const struct iov_iter *i, int maxpages) { … } int iov_iter_npages(const struct iov_iter *i, int maxpages) { … } EXPORT_SYMBOL(…); const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) { … } EXPORT_SYMBOL(…); static __noclone int copy_compat_iovec_from_user(struct iovec *iov, const struct iovec __user *uvec, u32 nr_segs) { … } static __noclone int copy_iovec_from_user(struct iovec *iov, const struct iovec __user *uiov, unsigned long nr_segs) { … } struct iovec *iovec_from_user(const struct iovec __user *uvec, unsigned long nr_segs, unsigned long fast_segs, struct iovec *fast_iov, bool compat) { … } /* * Single segment iovec supplied by the user, import it as ITER_UBUF. */ static ssize_t __import_iovec_ubuf(int type, const struct iovec __user *uvec, struct iovec **iovp, struct iov_iter *i, bool compat) { … } ssize_t __import_iovec(int type, const struct iovec __user *uvec, unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, struct iov_iter *i, bool compat) { … } /** * import_iovec() - Copy an array of &struct iovec from userspace * into the kernel, check that it is valid, and initialize a new * &struct iov_iter iterator to access it. * * @type: One of %READ or %WRITE. * @uvec: Pointer to the userspace array. * @nr_segs: Number of elements in userspace array. * @fast_segs: Number of elements in @iov. * @iovp: (input and output parameter) Pointer to pointer to (usually small * on-stack) kernel array. * @i: Pointer to iterator that will be initialized on success. * * If the array pointed to by *@iov is large enough to hold all @nr_segs, * then this function places %NULL in *@iov on return. Otherwise, a new * array will be allocated and the result placed in *@iov. This means that * the caller may call kfree() on *@iov regardless of whether the small * on-stack array was used or not (and regardless of whether this function * returns an error or not). * * Return: Negative error code on error, bytes imported on success */ ssize_t import_iovec(int type, const struct iovec __user *uvec, unsigned nr_segs, unsigned fast_segs, struct iovec **iovp, struct iov_iter *i) { … } EXPORT_SYMBOL(…); int import_ubuf(int rw, void __user *buf, size_t len, struct iov_iter *i) { … } EXPORT_SYMBOL_GPL(…); /** * iov_iter_restore() - Restore a &struct iov_iter to the same state as when * iov_iter_save_state() was called. * * @i: &struct iov_iter to restore * @state: state to restore from * * Used after iov_iter_save_state() to bring restore @i, if operations may * have advanced it. * * Note: only works on ITER_IOVEC, ITER_BVEC, and ITER_KVEC */ void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state) { … } /* * Extract a list of contiguous pages from an ITER_XARRAY iterator. This does not * get references on the pages, nor does it get a pin on them. */ static ssize_t iov_iter_extract_xarray_pages(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, iov_iter_extraction_t extraction_flags, size_t *offset0) { … } /* * Extract a list of contiguous pages from an ITER_BVEC iterator. This does * not get references on the pages, nor does it get a pin on them. */ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, iov_iter_extraction_t extraction_flags, size_t *offset0) { … } /* * Extract a list of virtually contiguous pages from an ITER_KVEC iterator. * This does not get references on the pages, nor does it get a pin on them. */ static ssize_t iov_iter_extract_kvec_pages(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, iov_iter_extraction_t extraction_flags, size_t *offset0) { … } /* * Extract a list of contiguous pages from a user iterator and get a pin on * each of them. This should only be used if the iterator is user-backed * (IOBUF/UBUF). * * It does not get refs on the pages, but the pages must be unpinned by the * caller once the transfer is complete. * * This is safe to be used where background IO/DMA *is* going to be modifying * the buffer; using a pin rather than a ref makes forces fork() to give the * child a copy of the page. */ static ssize_t iov_iter_extract_user_pages(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, iov_iter_extraction_t extraction_flags, size_t *offset0) { … } /** * iov_iter_extract_pages - Extract a list of contiguous pages from an iterator * @i: The iterator to extract from * @pages: Where to return the list of pages * @maxsize: The maximum amount of iterator to extract * @maxpages: The maximum size of the list of pages * @extraction_flags: Flags to qualify request * @offset0: Where to return the starting offset into (*@pages)[0] * * Extract a list of contiguous pages from the current point of the iterator, * advancing the iterator. The maximum number of pages and the maximum amount * of page contents can be set. * * If *@pages is NULL, a page list will be allocated to the required size and * *@pages will be set to its base. If *@pages is not NULL, it will be assumed * that the caller allocated a page list at least @maxpages in size and this * will be filled in. * * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA * be allowed on the pages extracted. * * The iov_iter_extract_will_pin() function can be used to query how cleanup * should be performed. * * Extra refs or pins on the pages may be obtained as follows: * * (*) If the iterator is user-backed (ITER_IOVEC/ITER_UBUF), pins will be * added to the pages, but refs will not be taken. * iov_iter_extract_will_pin() will return true. * * (*) If the iterator is ITER_KVEC, ITER_BVEC or ITER_XARRAY, the pages are * merely listed; no extra refs or pins are obtained. * iov_iter_extract_will_pin() will return 0. * * Note also: * * (*) Use with ITER_DISCARD is not supported as that has no content. * * On success, the function sets *@pages to the new pagelist, if allocated, and * sets *offset0 to the offset into the first page. * * It may also return -ENOMEM and -EFAULT. */ ssize_t iov_iter_extract_pages(struct iov_iter *i, struct page ***pages, size_t maxsize, unsigned int maxpages, iov_iter_extraction_t extraction_flags, size_t *offset0) { … } EXPORT_SYMBOL_GPL(…);
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